1. Field of the Invention
The present invention relates to an ink jet printer, a method of controlling an ink jet printer, and a computer program product for an ink jet printer.
2. Description of the Related Art
Ink jet printers are well known ink jet printer comprises an ink jet head. The ink jet head has a nozzle for discharging ink. The ink jet head discharges ink and thereby prints on a print medium such as a paper.
If the ink jet printer is not used for a long time, an ink solvent within an ink passage of the ink jet head may evaporate. If the ink solvent evaporates, the viscosity of the ink increases, and the ink will not flow smoothly. If the ink within the ink passage does not flow smoothly, the ink is not discharged smoothly from the ink jet head. If the ink is not discharged smoothly, a printing quality deteriorates.
In order to solve the above problem, a technique in which an ink discharging ability of the ink jet head is recovered automatically was developed (see Japanese Patent Application Publication No. H07-68795; U.S. Pat. No. 5,896,143). In this technique, the ink within the ink passage is sucked away from the nozzle of the ink jet head each time a predetermined time has elapsed. Since ink with increased viscosity is sucked away and the ink discharging ability is therefore recovered, ink can be discharged smoothly at the time of a next printing.